The invention relates to a fluid operated pump. More particularly, the invention relates to a pump which employs the pressure of one fluid to move another fluid in an efficient and inexpensive manner.
Moving fluid is an engineering problem which has been studied for thousands of years. During that time, countless xe2x80x9cpumpsxe2x80x9d have been devised which seek to move fluid using a variety of different energy sources. From windmills to electrostatics, pumps have taken many forms.
The most basic pump employs mechanical energy to move a fluid. The mechanical energy is often supplied by an electric motor which turns a turbine. However, different pumping schemes have been developed to meet the specific goals required by more demanding applications. Such goals include isolation of hazardous and corrosive substances, maintaining sterility in biomedical applications, providing a continuous flow which is free from surges, etc.
One general class of pump which has been developed is the peristaltic pump. Peristaltic pumps move a fluid within a tube by actually squeezing the tube itself. The squeezing is performed sequentially or continuously along the tube to urge the fluid to move in the direction that the squeezing progresses. Generally the tube is squeezed by mechanical action, wherein rollers are employed to engage the tube. Such a pump requires a complex mechanism to operate, and therefore is expensive to manufacture. In addition, the repeated mechanical contact with the tube causes wear upon said tube and limits the effective life of the pump.
One non-mechanical variation on the peristaltic pump is disclosed in U.S. Pat. No. 4,515,536 to van Os. This device employs fluid pressure to compress a hose. The hose has a supply end and a discharge end. Fluid pressure is gradually applied upon the hose starting at the supply end to urge fluid within the hose toward the discharge end. However, the complexity and fluid dynamic precision required for operation make this device unreliable and impractical.
U.S. Pat. No. 3,039,309 to Vesper et al. discloses a pneumatically actuated pump and sampling system. Vesper discloses a flow-through pump of considerable complexity, requiring a tight fit between its elastic hose and housing, as well as a sequencing system to precisely supply pressure at several different points at different times during the pumping sequence.
U.S. Pat. No. 3,406,633 to Schomburg discloses a collapsible chamber pump which employs pressure from a cam operated piston to compress a chamber. The chamber allows flow through the chamber in one direction only using a single check valve. However, if the tube is not designed for controlled collapse, much of the energy exerted will be wasted on backpressure, and will likely cause unwanted backflow.
While these units may be suitable for the particular purpose employed, or for general use, they would not be as suitable for the purposes of the present invention as disclosed hereafter.
It is an object of the invention to produce a pump which can effectively move a pumped fluid using a pumping fluid with no contact between said fluids. Accordingly, the pumped fluid is completely isolated from the pumping fluid.
It is another object of the invention to provide a pump which is inexpensive to manufacture and operate, and is configured for durability and reliability. Accordingly, the pump employs minimal working parts, and thus is inexpensive to manufacture and reliable in use.
It is another object of the invention to provide a pump which is capable of harnessing energy from an air or liquid source. Accordingly, the pump configuration is directly adaptable for hydraulic and pneumatic pumping fluid operation.
It is yet another object of the invention to provide a pump which can create a significant vacuum at its pump inlet while pumping a gas or a liquid, without requiring a flooded inlet, and without cavitation.
The invention is a pump, for moving a pumped fluid using a pumping fluid, comprising an outer housing defining an interior volume. A compressible main tube, having an interior space, is located within the outer housing. Inlet and exit valves, both having internal check valves, are in communication with the interior space of the compressible main tube. The outer housing is selectively filled with pressurized pumping fluid through a drive intake to compress the main tube and force pumped fluid contained therein out through the exit valve. The pressurized pumping fluid is then released through a bleeder valve to relieve pressure upon the main tube, allowing it to expand, and causing it to draw pumped fluid into its interior space through the inlet valve. Reiteration of these steps is controlled by a solenoid valve which selectively allows or prevents flow of the pumping fluid through the drive intake into the internal volume of the outer housing.
To the accomplishment of the above and related objects the invention may be embodied in the form illustrated in the accompanying drawings. Attention is called to the fact, however, that the drawings are illustrative only. Variations are contemplated as being part of the invention, limited only by the scope of the claims.